1. Field of the Invention
The present invention relates to apparatus and methods for measuring rotational speed with a fiber optic Sagnac interferometer. More particularly, this invention pertains to apparatus and methods for stabilizing the scale factor and loop gain of the control loop of a fiber optic Sagnac interferometer with phase resetting.
2. Description of the Prior Art
European patent publication EP-A1-0,441,998 discloses a fiber optic Sagnac interferometer suitable for inertial rotational speed measurement and also known for short as a fiber-optic gyro. In that device, bias errors and deadbands caused by electromagnetic overcoupling based thereupon are removed through a modulation method controlled by a random number generator. The method guarantees the correlation freedom of a demodulator reference signal. Unfortunately, the solution described in the above-mention publication entails highly complex circuitry for the subassemblies that generate the modulation and demodulation signals and obtain a control signal for the scale factor control loop.